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arXiv 1006.0968astro-ph.CO
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核塌缩超新星的母体金属丰度的观测约束

Observational constraints on the progenitor metallicities of core-collapse supernovae

J. P. Anderson, R. A. Covarrubias, P. A. James, M. Hamuy, S. M. Habergham

摘要:

我们提出的核心坍缩超新星的祖金属丰度的限制。到目前为止,几乎所有的金属丰度约束都是通过间接方法推断出来的,如宿主星系的金属丰度梯度、宿主星系的光度或衍生的全球星系金属丰度。在这里,祖先的金属丰度是来自在附近的超新星的网站,从强发射线的比例在其主机HII regions.We主机HII地区的光谱,并讨论了这些对核心坍缩超新星祖先的性质的影响。总的来说,虽然我们发现,平均金属丰度的IBC型环境高于II型事件,这种差异小于在以前的研究中观察到的。平均金属丰度值只有0.06 dex差异,统计学显著性为~1.5 sigma,而使用KS检验,我们发现两种金属丰度分布与来自相同母体的分布略有一致(概率>10%)。这表明,在决定超新星类型时,母星的金属丰度并不是一个主要的参数,母星的质量和/或双星度起着更重要的作用。

英文摘要:

We present constraints on the progenitor metallicities of core-collapse supernovae. To date, nearly all metallicity constraints have been inferred from indirect methods such as metallicity gradients in host galaxies, luminosities of host galaxies, or derived global galaxy metallicities. Here, progenitor metallicities are derived from optical spectra taken at the sites of nearby supernovae, from the ratio of strong emission lines found in their host HII regions.We present results from the spectra of 74 host HII regions and discuss the implications that these have on the nature of core-collapse supernova progenitors. Overall, while we find that the mean metallicity of type Ibc environments is higher than that of type II events, this difference is smaller than observed in previous studies. There is only a 0.06 dex difference in the mean metallicity values, at a statistical significance of ~1.5 sigma, while using a KS-test we find that the two metallicity distributions are marginally consistent with being drawn from the same parent population (probability >10%). This argues that progenitor metallicity is not a dominant parameter in deciding supernovae type, with progenitor mass and/or binarity playing a much more significant role.

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